The present invention relates in general to heating equipment and in particular to a new and useful steam heating apparatus which utilizes a condensed liquid vessel which is under atmospheric pressure and which is connected to a steam generator through a liquid circulation pipe or return line, for replenishing heat media liquid in the steam generater.
Steam type heating equipment is publicly known wherein water is heated by a steam boiler for the generation of steam which is then introduced into radiators or heat emitters. Latent heat is given off to the ambient air by condensing the steam in the aforesaid radiators or heat emitters and thus heating is achieved. This sort of steam type heating equipment adopts means wherein the condensed water is recirculated to the steam boiler by utilizing a circulation pump. Consequently, most of the noise and trouble of the heating system is due to the circulation pump. Further, electric power must be consumed for operating the circulation pump.
To avoid the circulation pump, steam type heating equipment is known which has a gravity liquid circulation system as shown in FIG. 1.
In FIG. 1, the symbol 01 indicates a steam generator, 02 a heating source and 03 a steam conducting pipe incorporating a heat transfer tube 05 of a heat radiator 04 for receiving saturated steam generated from the steam generator 01. A liquid circulation pipe 06 connects the outlet 09 of heat transfer tube 05 with the aforesaid steam generator 01. A vacuum air valve 07 is connected to outlet 09. Steam generator 01 has a steam outlet 08. a liquid return port 010 contains saturated steam 011. Condensed liquid is shown at 012. When the liquid inside steam generator 01 is heated up by the heating source 02 for generation of saturated steam 011, this saturated steam 011 is sent to the heat transfer tube 05 through the steam conducting pipe 03 for heat exchange with fluid around this heat transfer tube 05 (usually air) and for achieving the heating up effect by giving the condensed latent heat to the surrounding fluid and returning to a liquid phase, while the condensed liquid 012 is returned to the steam generator 01 because of the liquid level difference H between the condensed liquid level inside liquid circulation pipe 06 and that within steam generator 01.
This system, while avoiding the circulation pump, has installation restrictions in that the liquid level inside liquid circulation pipe 6 must be higher than the liquid level inside steam generator 01 by the pressure loss amount H of the pipe channel and further the radiator 04 must be erected on top of the liquid circulation pipe 06. In addition there is a defect of not being able to select a thinner dia pipe for the steam conducting pipe leading from the steam generator 01 to the radiator 04 because the radiator 04 (heat transfer tube 05) must have a small flow resistance since the aforesaid high H can not be set to a very larger value.
For this reason, the conventional gravity type liquid circulation system fails to cope with the increasing demands in recent years for a more compact heat emitter, a thinner diameter for pipe channels and a diversification of equipment.